1. Field of the Invention
The present invention relates generally to the field of rolled sheet materials, primarily those having individual sheets separated by perforation. More particularly, it concerns an apparatus for holding and dispensing paper towels or toilet paper.
2. Description of Related Art
It is desirable to have a holder and dispenser for rolled sheet materials such as paper towels, toilet paper and the like, in which a roll of sheet material may be pulled down easily to expose a sheet of material, and yet, a single sheet can be torn from the roll with the use of just one hand. Further, it is desirable to tear a single sheet of material without causing unwanted unrolling or free-spooling of additional sheets.
Previous holders and dispensers have largely been unsuccessful in this regard because they often lead to only partial separation of a sheet, or at the other extreme, excessive free spooling of additional sheets. Traditional holder and dispensers often rely upon frictional forces only to control tearing parameters. With traditional devices, a frictional force is applied at a fixed radius, generating a fixed frictional torque that resists a tearing force. On the other hand, tearing forces occur at an outer radius of a paper roll, generating a tearing torque that varies directly with the diameter of the roll of paper at the tear point.
Also retarding the unrolling of paper is the moment of inertia of the rolled sheet material itself. As the roll becomes thinner, this moment of inertia decreases. Traditional holder and dispensers often suffer from the familiar problem of unwanted spooling of extra sheets of paper when the roll is almost empty, particularly when the amount of paper remaining approaches a third to a half of a full roll. Traditional holder and dispensers also suffer from the familiar problem of tearing only a small portion of a sheet, rather than an entire perforated sheet, when a roll of paper is almost full.
Problems pointed out in the foregoing are not intended to be exhaustive but rather are among many that tend to impair the effectiveness of previously known holders and dispensers of rolled sheet material. Other noteworthy problems may also exist; however, those presented above should be sufficient to demonstrate that previous techniques appearing the art have not been altogether satisfactory, particularly in providing for tearing of complete sheets from a roll without unwanted spooling.